Power dissipation in the optical fibers of an optical network is inherently extremely small, even for relatively large optical power input to the fibers. Any power dissipation that does occur is spread over the lengths of the fibers, so that there is typically no concern about the effects of such dissipation.
On the other hand, other elements in the network, such as router line cards, optical amplifiers, or regenerators, may dissipate relatively large amounts of power, and the power dissipation may be in a small volume. One hub of an optical network, mounted in a cabinet, may easily dissipate 10 kW or more of power in the form of heat. Apart from the actual waste of power, some of which may be inherent in the design of the elements dissipating the power, there is a need to efficiently disperse the heat being generated to prevent over-heating. Forced convection with fans is typically used for the heat dispersal. Because of the nature of the equipment from which the heat is being dispersed, redundancy may typically be built into the forced convection system, adding to the overall cost of the optical network.
As the network elements which dissipate the power reduce in size, the problem of the heat generated, as well as the efficient dispersal of the heat, becomes more acute. There is thus a need to reduce power dissipation in an optical network as much as possible. Such reduction would preferably not affect communication aspects, such as a rate at which signals are transferred, of the network.